/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date:        19. March 2015
* $Revision: 	V.1.4.5
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_pid_init_q31.c
*
* Description:	Q31 PID Control initialization function
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*   - Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
*     the documentation and/or other materials provided with the
*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* ------------------------------------------------------------------- */

#include "arm_math.h"

/**
* @addtogroup PID
* @{
*/

/**
 * @brief  Initialization function for the Q31 PID Control.
 * @param[in,out] *S points to an instance of the Q31 PID structure.
 * @param[in]     resetStateFlag  flag to reset the state. 0 = no change in state 1 = reset the state.
 * @return none.
 * \par Description:
 * \par
 * The <code>resetStateFlag</code> specifies whether to set state to zero or not. \n
 * The function computes the structure fields: <code>A0</code>, <code>A1</code> <code>A2</code>
 * using the proportional gain( \c Kp), integral gain( \c Ki) and derivative gain( \c Kd)
 * also sets the state variables to all zeros.
 */

void arm_pid_init_q31(
    arm_pid_instance_q31 *S,
    int32_t resetStateFlag)
{

#ifndef ARM_MATH_CM0_FAMILY

    /* Run the below code for Cortex-M4 and Cortex-M3 */

    /* Derived coefficient A0 */
    S->A0 = __QADD(__QADD(S->Kp, S->Ki), S->Kd);

    /* Derived coefficient A1 */
    S->A1 = -__QADD(__QADD(S->Kd, S->Kd), S->Kp);


#else

    /* Run the below code for Cortex-M0 */

    q31_t temp;

    /* Derived coefficient A0 */
    temp = clip_q63_to_q31((q63_t) S->Kp + S->Ki);
    S->A0 = clip_q63_to_q31((q63_t) temp + S->Kd);

    /* Derived coefficient A1 */
    temp = clip_q63_to_q31((q63_t) S->Kd + S->Kd);
    S->A1 = -clip_q63_to_q31((q63_t) temp + S->Kp);

#endif /* #ifndef ARM_MATH_CM0_FAMILY */

    /* Derived coefficient A2 */
    S->A2 = S->Kd;

    /* Check whether state needs reset or not */
    if(resetStateFlag)
    {
        /* Clear the state buffer.  The size will be always 3 samples */
        memset(S->state, 0, 3u * sizeof(q31_t));
    }

}

/**
 * @} end of PID group
 */
